Photochromic plastic materials

ABSTRACT

A method for producing photochromic plastic materials is disclosed which is characterized by forming a transparent polymeric shape from a mixed polymer consisting of a polyester resin made by esterification of an unsaturated polybasic organic acid with a polyhydric alcohol, and a polar vinyl monomer, swelling a surface layer of the cured polymeric shape with a polar solvent, absorbing silver and halide ions into the swelled surface layer, and collapsing the swelled surface layer.

BACKGROUND OF THE INVENTION

This invention relates to a light sensitive plastic element whoseabsorbance varies directly with the intensity of ambient activatingradiation. More particularly, it relates to transparent polymericmaterials having photosensitive silver halide absorbed into thestructure of the surface layer thereof, which silver halide can undergoa reversible, light induced chemical change wherein light absorbingspecies and nonabsorbing species are alternately produced depending onthe intensity of ambient electromagnetic radiation.

Silver halides have several advantages over organic photochromicmaterials as an operative photochromic element. First, when properlytreated, they are inherently stable and hence fatigue free, i.e., do notlose their photochromic properties in repeated exposures to activatingradiation. Second, on activation, the light transmittance of silverhalide based photochromic articles decreases over the entire visiblespectrum resulting in activated gray or gray-brown shades.

Attempts to impart silver halide based photochromic properties towindows, lenses and other articles made from transparent polymericmaterials have not, in general, been overly successful. While it is wellknown that silver halides undergo a chemical change which results in alight absorbing species, it is not altogether clear what features of theenvironment of such photosensitive silver halides must be controlled inorder to assure that the activated species, in the absence of activatingradiation, will return to its light transmissive state in a reasonableperiod of time.

One condition that seems to be important is that the silver halidecrystals must be shielded from the effects of the chemistry present inpolymerizing materials, i.e., catalysts and initiators, which in generalhave a deactivating effect on the photosensitive crystals. For thisreason, in contrast to the conditions present in silver halide basedphotochromic glass, it is not possible simply to form silver halidecrystals directly in prepolymers which thereafter may be polymerized toform optical devices.

Another aspect of the silver halide crystal environment which seems tobe important is that the material surrounding the photosensitivecrystals must define a barrier which can prevent any substantialdiffusion of halogen, since recombination of halogen and the activatedsilver species which is believed to occur during recovery is obviouslynot possible if the halogen is lost.

Still another important parameter is the size of the silver halidecrystal which is incorporated into the host material. In this regard, itappears that crystals over 1 micron in diameter either do not undergoreversible, light-activated reactions, or do so to a degree insufficientto impart significant photochromism to host materials.

SUMMARY OF THE INVENTION

In accordance with the present invention, it has been discovered thatcertain transparent polymers may, after formation, have silver halidebased photochromism imparted thereto by sequential immersion in a silversolution and a halide solution. The polymers with which this process isuseful comprise two classes of components which have been found to becritical. The first component comprises a transparent unsaturatedpolyester resin produced by esterification of a polybasic unsaturatedacid, e.g., maleic acid, with a polyhydric alcohol, e.g., ethyleneglycol. This resin, during formation, may optionally be mixed with up toabout 70 percent of one or more unsaturated vinyl monomers to formtranslucent copolymers, terpolymers, etc. The second component consistsof a polar vinyl monomer, e.g., compounds such as N-vinyl pyrrolidone,acrylic acid, etc.

As long as the ratio of the first component to the second is kept withinthe range of between about 0.1 and 100, mixed copolymers result whichare characterized by a structure which can absorb silver and halide ionsand thereafter exhibit photochromic behavior.

The reasons why this particular polymer mixture is useful in the processis not thoroughly understood. However, when the materials of theinvention are immersed in polar solvents such as methanol, a swellingoccurs which results in the formation of a gel structure on the surfaceof the material. From observations, it appears that there is noappreciable dissolving of the plastic structure in the solvent. Bothhalide and silver ions freely diffuse into this gel-like surfacestructure during immersion. The order of the two immersions is notparticularly important although best results are achieved by immersionfirst in halide solution and then in silver solution. The halide ionswhich are present in the structure after a first immersion react withsilver ions diffusing into the swelled surface layer during a subsequentimmersion to form insoluble silver halide particles. Unpredictably, thedimensions of the gel pores or channels apparently are such that thegrowth of silver halide crystals is restricted to a size appropriate forexhibiting photochromism, i.e., 30 to 1000 Angstroms, or more likely,since no haziness is observed in optically clear polymers, 30 to 500Angstroms. After evaporation of the solvent phase of the silver andhalide solutions, the surface gel structures collapses, trapping thedesired silver halide particles in the surface layer of the plastic andproviding a photochromic material which exhibits rapid recovery.

Accordingly, it is an object of the invention to provide a process forproducing silver halide based photochromic plastic materials.

Another object of the invention is to provide photochromic plasticmaterials wherein the time necessary for the material to return to itsoriginal color after activation is advantageously short.

Still another object of the invention is to provide a family oftransparent plastics which may be rendered photochromic by sequentialimmersion in solutions of halide and silver ions.

Another object of the invention is to provide a method of treatingcertain optically clear plastic articles to impart photochromismthereto.

Another object of the invention is to provide a family of photochromiccoatings useful for imparting photochromic behavior to translucentarticles.

BRIEF DESCRIPTION OF THE DRAWING

The sole FIGURE of the drawing is a graph showing the spectraltransmittance of a photochromic plastic material embodying the inventionbefore and after activation and at 1 minute intervals during recovery.

DESCRIPTION OF THE PREFERRED EMBODIMENT

To fabricate the photochromic plastic materials of the invention, it isnecessary to first produce a transparent polymeric element containingtwo essential components: an unsaturated polyester resin produced byesterification of a polybasic unsaturated organic acid with a polyhydricalcohol; and a polar vinyl monomer of the type which forms polar solventsoluble plastic when homopolymerized. Those skilled in the art will havelittle difficulty selecting suitable components within these two generalcategories. Many species of the first component are availablecommercially and are distributed for use in, for example, encasingbiological specimens and forming optically clear lenses and otheroptical devices. One such polyester resin is available from Wards ofRochester, N.Y. under the tradename Bioplastic. Other suitable resinsmay be made by esterification of unsaturated acids such as maleic andfumaric acids with polyhydric alcohols, such as ethylene glycol,diethylene glycol, 2', 2'-dimethylpropanediol, etc. It should be pointedout that a very wide variety of polyester resins are useful, so long asthey are unsaturated in the acid monomer component as described.

Clear casting resins of this type are frequently partially polymerizedand mixed with one or more unsaturated vinyl monomers such as styrene,vinyl toluene, acrylic esters, methacrylic esters, vinyl acetate, etc.which to varying degrees impart desirable hardness to he polyesters.Styrenes are preferred hardening resins because of their low cost.Accordingly, up to 70% unsaturated vinyl monomer, based on the weight ofthe polyester, may be added to the polyester for conventional purposeswithout serious detriment to the photochromic plastics of the invention.Allyl type esters, such as diethylene glycol bis (allyl carbonate),diallyl maleate, diallyl fumarate, diallyl benzene phosphonate, etc.,copolymerized with vinyl type monomers are particularly useful.Diethylene glycol bis (allyl carbonate) forms copolymers withunsaturated vinyl type monomers which, advantageously, are opticallyclear, resistant to scratches, and particularly well adapted for theprocess of the invention.

The second critical component of the mixed polymer material of theinvention comprises vinyl monomers of the type having the generalformula: ##STR1## where R is a polar organic functionality and R', R"and R'" are hydrogen or a lower alkyl such as methyl or ethyl. Thefollowing polar vinyl monomers comprise nonlimiting examples of usefulcomponents:

1. N-vinyl pyrrolidone

2. vinyl acetate

3. vinyl succinamide

4. vinyl phthalimide

5. acrylic acid

6. 2-methacrylic acid

7. 3-methacrylic acid

8. vinylacetic acid

9. 3-vinylpropionic acid

10. 4-vinylpyridine

11. 5-vinyl-2-picoline

12. vinylformamide

13. vinylacetonitrile

14. acrylimide

When a transparent species of the class of the second component, orcompatible mixtures of such species, are mixed with a member of theclass of the first component in about a 0.1 to 100 (first component:second component) ratio by weight, a polymeric shape may be cast byadding various types of peroxide initiators and azo compounds, wellknown to those skilled in the art, to initiate polymerization.Nonlimiting examples of such initiators include acetyl benzoyl peroxide,paracetic acid, methyl ethyl ketone peroxide, cyclohexanone peroxide,and cyclohexyl hydroperoxides. Various activators and promoters may alsobe used for varying the curing properties of the polymers of theinvention in a known manner, e.g., cobalt salts may be used with ketoneperoxide.

In the process of the invention, a prepolymer mixture is prepared usingone or more species of the class disclosed above as the first componentwith or without an unsaturated vinyl monomer. After adding andthoroughly mixing a selected second component, polymerization iseffected in a mold of a desired shape, and, after the plastic shape hasgelled, it is removed from the mold and cured by conventionaltechniques.

Alternatively, prior to polymerizing the selected first and secondcomponent, the prepolymer mix may be coated on the surface of an articleto impart photochromic behavior thereto. This coating step may beaccomplished by any of the large number of known conventionaltechniques. Thereafter, polymerization is effected and the gelledcoating is cured.

The next step of the process is to swell a surface layer of thepolymeric shape or coating. This may be accomplished by immersing thematerial in a polar solvent, or preferably, by immersing the material ina solution of a polar solvent and either silver or halide ions. If thelatter procedure is followed, two solutions are prepared using a polarsolvent capable of both swelling the surface of the formed polymericshape and solubilizing silver and halide ions. The solutions may be madefrom the same polar solvents or different compatible ones. One shouldcontain halide ions chosen from the group consisting of bromide,chloride, iodide, and mixtures thereof. In addition, this solution maycontain one or more cations which, in accordance with known technology,are capable of serving as hole traps in silver halide photosensitiveparticles which sensitize the silver halide crystals to increasephotochromic behavior.

While a preferred solvent for these solutions is methanol, and whilemethanol is the only solvent employed in the examples which follow, itwill be apparent to those skilled in the art that other solvents will beuseful, e.g., water or ethanol, and that mixed polar solvents will beoperable. The best solvent for a particular polymer will depend on thenature of that polymer. In selecting a suitable solvent, it should bekept in mind that its function is to dissolve silver and halide ions andto swell the surface of the transparent material. Also, the selectedsolvent should have no deleterious effect on the light transmissiveproperties of the cast plastic material.

The cast plastic shape or coated article is then immersed in one of thetwo solutions for a sufficient amount of time to allow swelling of asurface layer thereof and absorption of the ions of interest. In thisregard, the duration of the immersion will generally be on the order ofbetween 2 minutes and 1/2 hour or more, depending on the solvent chosenand the composition of the plastic.

Thereafter, the plastic shape is thoroughly rinsed with the solvent toremove ions which have not been absorbed and then immersed in the secondsolution for a period of time generally on the order of 2 minutes to 1/2hour. During the second immersion, the ions of interest are absorbedinto a surface layer on the plastic material where they combined withthe ions from the first absorption to form fine silver halide crystalsin the pores of the polymeric material. After another thorough rinsing,the polymeric material is dried. A clear plastic shape or plastic coatedarticle is thereby formed, which, on irradiation with suitableactivating electromagnetic radiation, turns dark, and on removal of thesource of radiation, recovers in a few minutes to a few hours.

The invention will be further understood from the following exampleswhich are intended to be illustrative of the process of the inventionand should in no sense be construed as limiting.

EXAMPLE 1

A plastic plate was prepared by mixing 27.1 g of a polyester resin(Bioplastic from Wards, Rochester, N.Y.) with 12.9 g of the polar vinylmonomer, acrylic acid. This mixture was catalyzed with 2.8 g of methylethyl ketone peroxide, and the prepolymer mixture was poured into a flatglass mold with an internal thickness of 3 mm. After allowing 1 hour forthe forming material to reach the gel state, the soft plate was pickedfrom the mold and left to sit at room temperature for 40 hours.

The plate was then immersed in a 20% cupric chloride solution inmethanol at room temperature for 12 minutes. After removal from thecupric chloride-methanol bath, the plate was thoroughly rinsed withmethanol and then immersed in a saturated solution of silver nitrate inmethanol for 12 minutes at room temperature. After removal from thesilver nitrate bath, the plate was again thoroughly rinsed with methanoland heated in an oven at 90° C. for 15 minutes in order to removeimbibed methanol from the surface layers.

A plastic plate was produced which was perfectly transparent, light bluein color, and turned a brown color when activated by ultraviolet light.The spectral transmittance of this photochromic plastic material beforeand after activation, as well as at 1 minute intervals during recovery,is shown in the sole FIGURE of the drawing. The transmittance curve ofthe plastic plate prior to any irradiation is shown at A. Curve B showsthe transmittance of the plate after a 90 second irradiation with aBlack-Ray light from a distance of 2.5 cm. The transmittance curvesbetween curves A and B were taken at 1 minute intervals after theirradiation, i.e., during the recovery period. As can be seen from thegraph, the plate returned to essentially its original state in 20minutes.

EXAMPLE 2

A prepolymer mixture was prepared by dissolving 16 g of acrylic acid in24 g of Bioplastic. 2.8 g of methyl ethyl ketone peroxide were dissolvedin the mixture just prior to pouring it into a flat glass mold. Aftergellation had occurred, the soft plastic plate was picked from the moldand allowed to cure at room temperature for 20 hours.

The plate was then immersed in 20% cupric chloride solution in methanolfor 5 minutes. After thorough rinsing with methanol, it was immersed ina solution of methanol saturated with silver nitrate. After removal fromthe silver nitrate bath, it was again thoroughly rinsed with methanoland heated at 65° C. for 20 minutes. The formed plate showed moderatephotocoloration with a very fast thermal recovery (3-4 minutes).

EXAMPLE 3

The procedure for example 2 was repeated except that prior to imbibingthe halide and silver salts, the plate was cured at 65° C. for 3 hours.This more thorough curing process yielded a photochromic plate whichexhibiting stronger photocoloration then example 2, but which wascharacterized by a longer recovery period. (Approximately 20 minutes.)

EXAMPLE 4

The plastic formulation and curing cycle of this example was the same asin example 1, but the plate was first immersed in a saturated solutionof sodium chloride in methanol (rather than 20% cupric chloride as inexample 1) for 10 minutes. After removal and rinsing, it was immersedfor 10 minutes in a saturated silver nitrate solution in methanol. Theplastic was then dried at 67° C. for 15 minutes. The plate produced wasinitially colorless, but turned a dark brown shade upon exposure, at adistance of about 2 inches, to ultraviolet light produced by two 15-wattBlacklight lamps (F15T8. BLB manufactured by General ElectricCorporation), having an output of approximately 3 milliwatts per cm² inthe 3000-4000 Angstrom range. The sample showed complete recovery atroom temperature in approximately 30 minutes.

EXAMPLE 5

To 20 g of the Bioplastic polyester resin described above, 12 g ofacrylic acid and 8 g of dipropylene glycol were added together with 2.8g of methyl ethyl ketone peroxide. After gellation, the plastic platewas picked from the mold and allowed to cure at room temperature for 16hours; it was subsequently post cured at 67° C. for 5 hours.

The plate was then immersed in methanol saturated with sodium chloridefor 10 minutes. It was removed, rinsed, and subsequently immersed inmethanol saturated with silver nitrate for 10 minutes, after which itwas removed, rinsed again, and dried for 15 minutes at 67° C.

The colorless plate showed a strong photocoloration with a recovery rateof approximately 10 minutes.

EXAMPLE 6

To 20 g of Bioplastic were added 20 g of acrylic acid and 2.8 g ofmethyl ethyl ketone peroxide. The 3 mm thick plate produced was cured atroom temperature for 40 hours. The immersion treatment was the same asin example 5. The sample showed strong photocoloration and fast recovery(10 minutes) at room temperature.

EXAMPLE 7

24 g of Bioplastic were added together with 14 g of 3-methacrylic acidand 2.8 g of methyl ethyl ketone peroxide. A 3 mm thick plastic plateobtained from the above mixture, after curing at room temperature for 40hours, was immersed in a 20% cupric chloride solution in methanol for 12minutes. After thorough rinsing with methanol, it was subsequentlyimmersed in a saturated solution of silver nitrate in methanol for 12minutes. The plate was rinsed again and dried at 65° C. for 1/2 hour.Its photochromic properties were similar to those of the plate ofexample 1.

EXAMPLE 8

The procedure of example 7 was repeated except that in place of the3-methacrylic acid, vinylacetic acid was used. The photochromicproperties of the plastic were similar to those of example 1.

EXAMPLE 9

A solution of polyester resin was first prepared by mixing 70 g ofpoly(oxydiethylene maleate) and 30 g of styrene. The poly(oxydiethylenemaleate) was prepared by the condensation of diethylene glycol andmaleic anhydride by well-known methods.

A polymer mixture was then prepared by dissolving 15 g of acrylic acidin 25 g of the above polyester formulation. This mixture was thencatalyzed with 1.0 g of benzoyl peroxide, and the prepolymer mixturepoured into a glass lens-shaped (6-base) mold with internal thickness of2 mm. After allowing 2 hours for the mixture to reach a firm gel statethe plastic plano lens was picked from the mold and allowed to sit atroom temperature for 48 hours.

The immersion solutions and procedures were the same as that of example1 yielding a light blue colored lens which turned brown upon exposure tosunlight. It recovered its original transparency indoors inapproximately 30 minutes.

EXAMPLE 10

Twenty grams of the polyester-styrene mixture of example 9 were mixedwith 20 g of 3-methacrylic acid and catalyzed with 1.0 g of benzoylperoxide. The prepolymer mixture was cast in a glass lens-shaped moldwith an internal thickness of 2 mm. The plastic lens was allowed to cureat room temperature for 20 hours. The lens was postcured for 3 hours at65° C. The immersion solutions and imbibing procedures were the same asthose given in example 4. The initially colorless lens turned a darkbrown color within 3 minutes' exposure to bright sunlight and was nearlycompletely recovered when shielded from the sun in approximately 45minutes at 75° C.

EXAMPLE 11

A polyester resin based on poly(ethylene-oxydiethylenemaleate-phthalate-adipate) and styrene was prepared in the conventionalmanner by reacting 85 g ethylene glycol, 146 g diethylene glycol, 171 gmaleic anhydride, 56 g phthalic anhydride, and 55 g adipic acid.One-hundred grams of the above-reacted mixture was dissolved in 43 g ofstyrene to provide the working polyester formulation.

A polymerizing mixture was next prepared by dissolving 10 g of acrylicacid and 30 g of the above polyester formulation. The mixture wascatalyzed with 1.0 g of a 60% solution of methyl ethyl ketonhydroperoxide in dimethyl phthalate (Lupersol DDM). The prepolymermixture was cast in a flat glass mold of 3 mm internal thickness andallowed to cure at room temperature for 3 hours giving a hard, colorlessplastic plate.

The immersion solution and imbibing procedure were the same as thosegiven in example 4. The initially colorless plate turned a reddish brownshade upon exposure to ultraviolet light for several minutes andreturned to its original colorless condition when placed in the dark atroom temperature for 1 hour.

EXAMPLE 12

Twenty grams of the polyester formulation of example 11 were mixed with20 g of 4-vinylpepidine and 1.0 g of Lupersol DDM.

The polymerizing mixture was cast in a lens-shaped glass mold andallowed to cure for 1.5 hours at room temperature. The plastic lens thusformed was immersed in methanol saturated with sodium bromide for 5minutes. After rinsing with methanol it was subsequently immersed inmethanol saturated with silver nitrate for 5 minutes, rinsed thoroughlyand dried for 15 minutes at 67° C.

The lens changed from a light yellow color to a dark brown shade insunlight and recovered in approximately 20 minutes.

EXAMPLE 13

Fifteen grams of acrylic acid were dissolved in 25 g of diallyl diglycolcarbonate (CR-39). The mixture was catalyzed using 2.0 g of isopropylpercarbonate poured into a lens-shaped glass mold of 2 mm internalthickness and heated at 60° C. for 30 minutes, followed by 75° C. for 40minutes.

The immersion procedure was the same as that described in example No. 1with the lens exhibiting photochromic properties similar to the plasticplate of example No. 1.

EXAMPLE 14

The same as example 13; however, the immersion procedure of example 4was employed. The resultant lens exhibited photochromic propertiessimilar to photochromic plastic plate of example 4.

EXAMPLE 15

The same as example 14; however, the lens was additionally immersed for1 minute in an aqueous dispersion of Eastman Fast Blue B-GLF. Theresulting lens was a blue shade before activation but turned a dark graycolor upon exposure to bright sunlight for 3 to 4 minutes and recoveredin the dark.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics there of. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed is:
 1. A process for producing a photochromic plasticmaterial characterized by the steps of:forming a transparent polymericmaterial from:a first component consisting essentially of at least oneunsaturated polyester resin produced by esterification of a polybasic,unsaturated organic acid with a polyhydric alcohol, and a secondcomponent consisting essentially of a polar vinyl monomer; contactingsaid material with a solvent to swell a surface layer thereof;contacting said surface layer with halide ions chosen from the groupconsisting of chloride, iodide, bromide, and mixtures thereof;contacting said surface layer with silver ions; and removing retainedsolvents from said material to collapse said swelled surface layer. 2.The process as set forth in claim 1 wherein said polar vinyl monomer isselected from the group consisting of N-vinyl pyrrolidone, vinylacetate, vinyl succinamide, vinyl phthalimide, acrylic acid,2-methacrylic acid, 3-methacrylic acid, vinyl-acetic acid,3-vinylpropionic acid, 4-vinylpyridine, 5-vinyl 2-picoline,vinylformamide, vinylacetonitrile, acrylamide, and mixtures thereof. 3.The process as set forth in claim 1 wherein said polybasic unsaturatedorganic acid is selected from the group consisting of maleic acid,fumaric acid, and mixtures thereof.
 4. The process as set forth in claim1 wherein said polyhydric alcohol is selected from the group consistingof ethylene glycol, diethylene glycol, 2'2' dimethyl propanediol, andmixtures thereof.
 5. The process as set forth in claim 1 wherein saidhalide and silver ions are dissolved in a low molecular weight alcohol.6. The process as set forth in claim 5 wherein said low molecular weightalcohol is methanol.
 7. The process as set forth in claim 1 wherein saidfirst component is selected from the group consisting of resinsconsisting of diethylene glycol bis (allyl carbonate), diallyl maleate,diallyl fumarate, diallyl benzene phosphonate, and mixtures thereofcopolymerized with between 0 and about 70% of at least one unsaturatedvinyl monomer.
 8. The process as set forth in claim 7 wherein said firstcomponent consists essentially of diethylene glycol bis (allylcarbonate) copolymerized with between 5 and 50% of an unsaturated vinylmonomer.
 9. The process as set forth in claim 1 wherein said firstcomponent is copolymerized with between 0 and 70% of an unsaturatedvinyl monomer selected from the group consisting of styrene, vinyltoluene, acrylic esters, methacrylic esters, and mixtures thereof. 10.The process as set forth in claim 1 wherein the mass ratio of said firstcomponent to said second component is between 0.1 and
 100. 11. Theprocess as set forth in claim 1 wherein said forming step is effected bymixing said first and second component in a mold in the presence of aninitiator chosen from the group consisting of acetyl benzoyl peroxide,peracetic acid, methyl ethyl ketone peroxide, cyclohexanone peroxide,and cyclohexyl peroxide.
 12. A process for producing a photochromiccoating on the surface of an article, said process being characterizedby the steps of:forming a transparent polymeric coating on said articlefrom:a first component consisting essentially of at least oneunsaturated polyester resin produced by esterification of a polybasic,unsaturated organic acid with a polyhydric alcohol, and a secondcomponent consisting essentially of a polar vinyl monomer; contactingsaid coating with a solvent to swell a surface layer thereof; contactingsaid surface layer with halide ions chosen from the group consisting ofchloride, iodide, bromide, and mixtures thereof; contacting said surfacelayer with silver ions; and removing retained solvents from said coatingto collapse said swelled surface layer.
 13. The process as set forth inclaim 12 wherein said polar vinyl monomer is selected from the groupconsisting of N-vinyl pyrrolidone, vinyl acetate, vinyl succinamide,vinyl phthalimide, acrylic acid, 2-methacrylic acid, 3-methacrylic acid,vinyl-acetic acid, 3-vinylpropionic acid, 4-vinylpyridine, 5-vinyl 2picoline, vinylformamide, vinylacetonitrile, acrylamide, and mixturesthereof.
 14. The process as set forth in claim 12 wherein said polybasicunsaturated organic acid is selected from the group consisting of maleicacid, fumaric acid, and mixtures thereof.
 15. The process as set forthin claim 12 wherein said polyhydric alcohol is selected from the groupconsisting of ethylene glycol, diethylene glycol, 2'2' dimethylpropanediol, and mixtures thereof.
 16. The process as set forth in claim12 wherein said halide and silver ions are dissolved in a low molecularweight alcohol.
 17. The process as set forth in claim 16 wherein saidlow molecular weight alcohol is methanol.
 18. The process as set forthin claim 12 wherein said first component is selected from the groupconsisting of resins consisting of diethylene glycol bis (allylcarbonate), diallyl maleate, diallyl fumarate, diallyl benzenephosphonate, and mixtures thereof copolymerized with between 0 and about70% of at least one unsaturated vinyl monomer.
 19. The process as setforth in claim 18 wherein said first component consists essentially ofdiethylene glycol bis (allyl carbonate) copolymerized with between 5 and50% of an unsaturated vinyl monomer.
 20. The process as set forth inclaim 12 wherein said first component is copolymerized with between 0and 70% of an unsaturated vinyl monomer selected from the groupconsisting of styrene, vinyl toluene, acrylic esters, methacrylicesters, and mixtures thereof.
 21. The process as set forth in claim 12wherein the mass ratio of said first component to said second componentis between 0.1 and 100.